The purpose of this study is to determine if phototherapy (treatment with red light and a drug called hematoporphyrin derivative) will destroy cancer of the esophagus. Preliminary results are that we are able to eliminate Barrett's esophagus and high grade dysplasia. Superficial neoplasms are more difficult but we have been able to achieve this in the majority of patients. Currently, we are expanding the study to a multicenter randomized study of these patients.